I've actually never heard of anyone getting in trouble for owning original AK47 or AK74 orginal FCG parts(of course excluding the auto sear and rater reducer). In fact, it is perfectly legal to use the original fcg parts in a semi auto gun. Just have to make sure that your parts count is cochure with 922r. I think that if it were an issue, the larger distributors would pull these parts from the kits to avoid any possible legal situations. But, many use these parts especially in pistol builds(even though they were used in the original full-auto gun). If I were building a pistol from a Tantal, I would ensist on using the original parts that would match the rest of my SN's and would probably have as good or better trigger pull.

There are problems,however, with the above situation if this were invovled with an AR15. I'm pretty sure the ATF has already taken a stance on possessing M16 full auto parts while possessing an AR15.